Need PAR Help Please - Reading discrepancies Apogee vs Seneye

[DudeBoy]

I need some help here. Not sure what to set my lights to based on conflicting PAR measurements. Everything I've read and videos watched on Seneye show that it's within 10% of Apogee and I'm just not seeing that.


SUMMARY
- A couple months ago, I paid a dude to use his Apogee PAR meter on my aquarium and take several readings at several of my light settings. He did a great job and provided me a couple pictures of my 210g tank with overlay text showing the PAR readings at various location.
- Wife and I decided to add a large frag tank and that led me to purchase a seneye to use just for the PAR meter (which I received yesterday). I took baseline readings in my 210g tank at the same locations mentioned above with VERY different reading results.
- All Seneye readings were 20%-50% higher than the Apogee readings
- Yes....EVERYTHING is the same as it was a couple months ago besides adding a couple rocks against the back wall for additional frag placement.


DETAILS
- 210g display with 3, 165W LEDs (see link below)


- Picture from March 2nd of initial light settings and PAR readings with Apogee PAR meter

- After turning down the Whites from 15% to 1%, I am still quit getting higher PAR readings from the Seneye (see below picture, new text in white). As mentioned above, before reducing the white settings, I was seeing ~40% higher numbers everywhere.

 

[Clownreef]

There have been side by side comparisons before and apparently the discrepancies between an Apogee and a seneye aren’t that much far apart.

Turn off all circulation and check again.

 

[DudeBoy]

There have been side by side comparisons before and apparently the discrepancies between an Apogee and a seneye aren’t that much far apart.

Turn off all circulation and check again.

I did...all circulation was stopped and I agree with you....I saw the same videos which is why I was perplexed.....I even went so far as to reboot PC and power, unplug and replug in the seneye. I just dont understand the discrepancy. Do Apogee PAR meters have to be calibrated? Maybe this dude that helped me out just had an Apogee unit that was out of calibration? I feel good about the Seneye numbers. I've added several frags and this would explain some of the issues we've had with new frag placement and acclimation issues. I've adjusted my lights down due to the readings I'm getting with the Seneye. I'm hoping in the next few days I'll see the difference in the coral behavior.

 

[xiaoxiy]

Which Apogee meter was he using? The non-immersion Apogees don't have the immersion (under water) correction factor built in and need to have their values multiplied by 1.32. Also some of the older Apogee sensors have difficulties picking up the bluer spectrums that predominate reef lighting.

 

[richarddeweerd]

Didn't the BRS guys found a bug in the Apogee which caused the correction factor not being used at all, even if it was selected.

 

[DudeBoy]

Which Apogee meter was he using? The non-immersion Apogees don't have the immersion (under water) correction factor built in and need to have their values multiplied by 1.32. Also some of the older Apogee sensors have difficulties picking up the bluer spectrums that predominate reef lighting.

Apogee MQ-510 Full Spectrum Underwater LED PAR Meter

 

[DudeBoy]

Didn't the BRS guys found a bug in the Apogee which caused the correction factor not being used at all, even if it was selected.

not a clue. that would certainly explain a lot though....

 

[oreo54]

Didn't the BRS guys found a bug in the Apogee which caused the correction factor not being used at all, even if it was selected.

Putting the most popular PAR meters to the test | BRStv Investigates

Hey guys! Are you ready to explore differences in some of the most popular PAR meters? Watch as we put them to the test in a head-to-head comparison with our laboratory grade Li-Cor PAR meter! The results may surprise you!

www.reef2reef.com

In this process, we found that the Licor meter's software error explained some of the bad numbers in the video, but our testing also uncovered a small manufacturing defect in our 500 series sensors that has been causing low readings when measuring individual bulbs that are in the 400-420 nm range (such as deep-blue and violet "actinic" bulbs). This has been corrected in our sensors going forward, but if you already own an Apogee 500 series PAR meter and want to see if this issue significantly affects the measurements you are making, please see our site for more details. http://www.apogeeinstruments.com/apogee-instruments-500-quantum-series-product-announcement/

http://www.apogeeinstruments.com/apogee-instruments-500-quantum-series-product-announcement/

 

[DudeBoy]

I already feel better...thanks guys.....

 

[richarddeweerd]

I also feel better, I just got a Seneye delivered last week, mainly for the par readings.

 

[Aardvark1134]

If you watch the BRS video where they test 4 par meters it will tell you that even with the super expensive ones they are just for getting an estimate as none of them were close together and the 2 most expensive ones both had errors that caused them to be way off.
Also the seneye doesn't do will with light comming from an angle.

It's why I laugh when people say you need X par for y coral...with what spectrum and what brand model of meter and with which firmware version...without all that you can't get the same light level. Any reading I would consider to be + or - 20%

 

[jda]

The Apogee 510 had a bug. The serial numbers of the bad models were on their site. They were reading low. This was a few years ago. I have one that has been fixed.

Seneye is just inaccurate if you cannot square up the sensor - it is not cosine corrected. If you have calm water and can get it directly square at 90 degrees, then it is OK - this is why BRS has such good readings with them but not many of us have an acrylic grid system with holes and stuff to keep everything nice and square.

You always need to know what model of PAR meter is being used if you are going to compare anything outside of your tank.

 

[DudeBoy]

If you watch the BRS video where they test 4 par meters it will tell you that even with the super expensive ones they are just for getting an estimate as none of them were close together and the 2 most expensive ones both had errors that caused them to be way off.
Also the seneye doesn't do will with light comming from an angle.

It's why I laugh when people say you need X par for y coral...with what spectrum and what brand model of meter and with which firmware version...without all that you can't get the same light level. Any reading I would consider to be + or - 20%

I agree with you but I was getting some reading that were nearly double. I know this is a "just for reference" tool but I was waaaay off in some situations....the perfect storm perhaps. Either way, I do feel better about using the Seneye readings.

 

[Miller535]

not a clue. that would certainly explain a lot though....

The bug is with the Li-cor not that apogee

 

[DudeBoy]

The bug is with the Li-cor not that apogee

I watched the video in the link and I thought it mentioned that the Apogee 500 series also had issues that underestimated the blue light spectrum....this would explain the variance in the readings that I was getting....right? I thought that's why BRS didnt include the 500 series in any of the second wave of tests.

 

[Miller535]

I watched the video in the link and I thought it mentioned that the Apogee 500 series also had issues that underestimated the blue light spectrum....this would explain the variance in the readings that I was getting....right? I thought that's why BRS didnt include the 500 series in any of the second wave of tests.

They said users said it underreported the blue and uv, but showed in their graph that it covered most of the spectrum. And Ryan said in the video that they didn't include the 500 because they didnt have a working one in their lab.

 

[Aardvark1134]

Well in 1 of the BRS videos they took out the 500 and the licor because both were reporting way off due to issues and needed an update.

 

[oreo54]

Well in 1 of the BRS videos they took out the 500 and the licor because both were reporting way off due to issues and needed an update.

Licor wasn't applying the immersion correction factor even if "clicked on" in software.
I believe it was over the course of years. HOW embarrassing is that

 

[Aardvark1134]

What you mean is the gold standard that costs a much as a cheap car that almost all professionals with PHDs were using was off by like 35% for years and none of the professionals even noticed...I also bet none of them recalled or corrected any of their papers that were off by almost 1/3.